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Background: Alzheimer's disease (AD) is an increasingly common type of dementia. Apolipoprotein E (APOE) gene is a strong risk factor for AD. Objective: Here, we explored alterations in grey matter structure (GMV) and networks in AD, as well as the effects of the APOEɛ4 allele on neuroimaging regions based on structural magnetic resonance imaging (sMRI). Methods: All subjects underwent an sMRI scan. GMV and cortical thickness were calculated using voxel-based morphological analysis, and structural networks were constructed based on graph theory analysis to compare differences between AD and normal controls. Results: The volumes of grey matter in the bilateral inferior temporal gyrus, right middle temporal gyrus, right inferior parietal lobule, right limbic lobe, right frontal lobe, left anterior cingulate gyrus, and bilateral olfactory cortex of patients with AD were significantly decreased. The cortical thickness in patients with AD was significantly reduced in the left lateral occipital lobe, inferior parietal lobe, orbitofrontal region, precuneus, superior parietal gyrus, right precentral gyrus, middle temporal gyrus, pars opercularis gyrus, insular gyrus, superior marginal gyrus, bilateral fusiform gyrus, and superior frontal gyrus. In terms of local properties, there were significant differences between the AD and control groups in these areas, including the right bank, right temporalis pole, bilateral middle temporal gyrus, right transverse temporal gyrus, left postcentral gyrus, and left parahippocampal gyrus. Conclusion: There were significant differences in the morphological and structural covariate networks between AD patients and healthy controls under APOEɛ4 allele effects. [ABSTRACT FROM AUTHOR]

Oligomeric amyloid-β (OAβ), an upstream driver of Alzheimer's disease (AD) neuropathology, correlates with poor cognitive performance and brain volume reduction. Its effect on cognitive performance measured by the language neutral Visual Cognitive Assessment Test (VCAT) remains to be evaluated. We studied the correlation of plasma OAβ with VCAT scores and grey matter volume (GMV) in a Southeast Asian cohort with mild cognitive impairment. Higher plasma OAβ significantly correlated with lower; cognitive scores (VCAT, Mini-Mental State Examination) and GMV/intracranial volume ratio. Such findings reveal the clinical utility of plasma OAβ as a promising biomarker and support validation through longitudinal studies. [ABSTRACT FROM AUTHOR]

Background: Allele ɛ4 of the apolipoprotein (APOE∈4) gene is the strongest known genetic risk factor for late-onset sporadic Alzheimer's disease. A possible relationship between vitamin D and APOE is not yet clear.Objective: In this exploratory, cross-sectional study, we examined the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and brain volumes and the associations of both serum levels of 25(OH)D and APOE polymorphism to brain volumes in 127 persons (mean age 66 years) with cognitive symptoms.Methods: All subjects were examined with fully automated software for MRI volumetry, NeuroQuant.Results: After adjustment for relevant covariates, higher serum 25(OH)D levels were associated with greater volumes of cortical gray matter on both left (p = 0.02) and right (p = 0.04) sides. When both 25(OH)D levels and APOE genotype were used as the main covariates, no significant associations were found between vitamin D level and brain volume in any of the 11 brain regions. In adjusted models, only homozygous but not heterozygous APOE∈4 allele carriers had significantly larger inferior lateral ventricles (p = 0.003) and smaller hippocampal volume (p = 0.035) than those without ɛ4. Homozygous APOE∈4 carriers also had significantly higher vitamin D levels (p = 0.009) compared to persons without the APOE∈4 allele.Conclusion: Higher vitamin D levels might have a preserving effect on cortical grey matter volume. [ABSTRACT FROM AUTHOR]

Late-life depression, even when of subsyndromal severity, has shown strong associations with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Preclinical studies have suggested that serotonin selective reuptake inhibitors (SSRIs) can attenuate amyloidogenesis. Therefore, we aimed to investigate the effect of SSRI medication on amyloidosis and grey matter volume in subsyndromal depressed subjects with MCI and AD during an interval of two years. 256 cognitively affected subjects (225 MCI/ 31 AD) undergoing [18F]-AV45-PET and MRI at baseline and 2-year follow-up were selected from the ADNI database. Subjects with a positive depression item (DEP(+); n = 73) in the Neuropsychiatric Inventory Questionnaire were subdivided to those receiving SSRI medication (SSRI(+); n = 24) and those without SSRI treatment (SSRI(-); n = 49). Longitudinal cognition (Δ-ADAS), amyloid deposition rate (standardized uptake value, using white matter as reference region (SUVRWM), and changes in grey matter volume were compared using common covariates. Analyses were performed separately in all subjects and in the subgroup of amyloid-positive subjects. Cognitive performance in DEP(+)/SSRI(+) subjects (Δ-ADAS: -5.0%) showed less deterioration with 2-year follow-up when compared to DEP(+)/SSRI(-) subjects (Δ-ADAS: +18.6%, p < 0.05), independent of amyloid SUVRWM at baseline. With SSRI treatment, the progression of grey matter atrophy was reduced (-0.9% versus -2.7%, p < 0.05), notably in fronto-temporal cortex. A slight trend towards lower amyloid deposition rate was observed in DEP(+)/SSRI(+) subjects versus DEP(+)/SSRI(-). Despite the lack of effect to amyloid PET, SSRI medication distinctly rescued the declining cognitive performance in cognitively affected patients with depressive symptoms, and likewise attenuated grey matter atrophy. [ABSTRACT FROM AUTHOR]

Searching for biomarkers sensitive to early Alzheimer's disease (AD) and its progression has been a research priority for two decades. MRI has been increasingly used for this endeavor because of its capability of detecting both structural and functional brain patterns without injecting external contrast agent or radioactive tracers. Recent work has shown sensitivity of hippocampal volume and regional cerebral blood flow for differentiating prodromal AD from normal controls as well as AD. This review provides a summary for the existing literature describing the applications of either or both modalities in early AD studies as well as disease progression assessment. The various findings in the reviewed studies lead to a conclusion of assessing hippocampal volume and arterial spin labeling cerebral blood flow as potential markers for disease detection, and progression monitoring though longitudinal studies are still lacking to fully examine their sensitivity and specificity. [ABSTRACT FROM AUTHOR]